I am 19 years old and have had one miss carrige when I was 16 seems like I can never get pregnant, it seems like I'm being punished I do have quite a lot of sex but never seem to get a lucky day. Am I doing something wrong? What can I do different , my periods are always bang on time but no idea when I'm ovulating as I'm always stressed. What to do ? X

I think you have answered your own question.

You don't know when you are ovulating
You are stressed
You are only 19

For many people it can take YEARS to get pregnant.
If you are concerned talk to your doctor, make sure everything is right with both you and your partner and start from there.

I will spare you the speech, but is there a reason you are trying so hard to get pregnant when you are so young?

For so many they get pregnant the first time they have sex, others can take years.

Also merely having "a lot" of sex is not the answer, it is having sex on the right day to increase the odds. In fact not having sex before to help increase sperm count. So having it all the time ( assuming it is the same man) will actually hurt the chances